A communications system, for example, Wideband Code Division Multiple Access (WCDMA), is a self-interference system. Service quality of a user may be improved by improving transmit power of the user equipment (UE). However, at the same time, interference to the system may also increase, and therefore, the power needs to be controlled to improve system performance.
In the prior art, a method combining outer loop power control and inner loop power control is used to perform power control. Specifically, in the outer loop power control, a target signal-to-interference ratio (SIR) of the inner loop power control is adjusted according to an actual bit error rate (BER) and a preset target BER. If the actual BER is greater than the target BER, the target SIR of the inner loop power control is increased, and otherwise, the target SIR of the inner loop power control is decreased. In the inner loop power control, inner loop power control is performed according to an actual SIR and an adjusted target SIR that is obtained by means of the outer loop power control, so that the UE increases or reduces the transmit power according to the inner loop power control to improve the system performance.
However, when power control is being performed by using the foregoing prior art, a problem of relatively low power control accuracy often occurs, and target quality required by a system cannot be correctly converged.